3.2 KiB
Paginating A List
Adding pagination to a [api:SS_List] is quite simple. All
you need to do is wrap the object in a [api:PaginatedList] decorator, which takes
care of fetching a sub-set of the total list and presenting it to the template.
In order to create a paginated list, you can create a method on your controller
that first creates a SS_List that will return all pages, and then wraps it
in a [api:PaginatedList] object. The PaginatedList object is also passed the
HTTP request object so it can read the current page information from the
"?start=" GET var.
The paginator will automatically set up query limits and read the request for information.
:::php
/**
* Returns a paginated list of all pages in the site.
*/
public function PaginatedPages() {
return new PaginatedList(Page::get(), $this->request);
}
Note that the concept of "pages" used in pagination does not necessarily
mean that we're dealing with Page classes, its just a term to describe
a sub-collection of the list.
Setting Up The Template
Now all that remains is to render this list into a template, along with pagination
controls. There are two ways to generate pagination controls:
[api:PaginatedList->Pages()] and [api:PaginatedList->PaginationSummary()]. In
this example we will use PaginationSummary().
The first step is to simply list the objects in the template:
:::ss
<ul>
<% loop $PaginatedPages %>
<li><a href="$Link">$Title</a></li>
<% end_loop %>
</ul>
By default this will display 10 pages at a time. The next step is to add pagination controls below this so the user can switch between pages:
:::ss
<% if $PaginatedPages.MoreThanOnePage %>
<% if $PaginatedPages.NotFirstPage %>
<a class="prev" href="$PaginatedPages.PrevLink">Prev</a>
<% end_if %>
<% loop $PaginatedPages.Pages %>
<% if $CurrentBool %>
$PageNum
<% else %>
<% if $Link %>
<a href="$Link">$PageNum</a>
<% else %>
...
<% end_if %>
<% end_if %>
<% end_loop %>
<% if $PaginatedPages.NotLastPage %>
<a class="next" href="$PaginatedPages.NextLink">Next</a>
<% end_if %>
<% end_if %>
If there is more than one page, this block will render a set of pagination
controls in the form [1] ... [3] [4] [[5]] [6] [7] ... [10].
Paginating Custom Lists
In some situations where you are generating the list yourself, the underlying
list will already contain only the items that you wish to display on the current
page. In this situation the automatic limiting done by [api:PaginatedList]
will break the pagination. You can disable automatic limiting using the
[api:PaginatedList->setLimitItems()] method when using custom lists.
Setting the limit of items to be displayed on a page
To set the limit of items displayed in a paginated page use the [api:PaginatedList->setPageLength()] method. e.g:
:::php
/**
* Returns a paginated list of all pages in the site, and limits the items displayed to 4 per page.
*/
public function PaginatedPagesLimit() {
$paginatedItems = new PaginatedList(Page::get(), $this->request);
$paginatedItems->setPageLength(4);
return $paginatedItems;
}